Heat indicator for internal-combustion engines



June 18, 1929. ESHBAUGH ET ALv 1,717,670-

HEAT INDICATOR FOR INTERNAL COMBUSTION ENGINES Filed Feb, 5, 1927 3mm 5 f/p azm/ 5 fly .s' 724x274 a ni' w gbw/ Gummy Patented June 18, 1929.

UNITED STATES PATENT forrlcu.

JESSE EVERETT IESHBAUGH AND HERMAN C. GAN'IZ, OF FLINT, MICHIGAN, ASSIGN- I OBS TO A C SPARK PLUG COMEANY, OF FLINT, MICHIGAN, A COMPANY OF.MIOHI- GAN.

HEAT INDICATOR FOR INTERNAL-COMBUSTION ENGINES.

Application filed February 5, i927. Serial No. 186,173.

This invention relates to improvements in heat indicators for internal combustion engines, particularly to engines used on automotive vehicles, y

In carrying out our invention we makeuse of a type of indicator which changes the color of a painted surface due to the application of heat above a certain temperature. This change in color due to heat application is a well known property of certain paint substances and for convenience we position this indicator in the top opening or cap of the radiator so that it may be readily observed by the chauflfer.

Heat indicators placed in a similar position have been in use for some years, however, the prior devices largely making use of a thermostatic instrument such as a thermometer the bulb of which is held in the air space over the Water in the radiator. In our device we make use of a tube, preferably metallic, having a loop or hook at its upper portion projecting through the radiator cap or closure. This projecting portion has a heat sensitive paint applied to a part of its surface or to a member attached thereto so that when the temperature within the radiator rises abovea certain point the coloro'f the painted surface will change indicating to the chauiler that the danger point has been reached.

The accompanying drawing shows three species of our device and in each modification one end of the tube is open and exposed to the air space above the water or" the radia-. tor while the other end of the tube may be disposed below the surface of the water or connected to theoverfiow pipe.

We also, in some instances, make use of a glass section in the loop end of my tube, this section being exposed to the cooling effect of the atmosphere, and as the water 'vapor passes through the tube it will'be condensed and formed into drops which will pass along the tube and back into'the radiator. The fiow of these drops through the glass tube will indicate to the driver that the high temperature point has been reached.

Our invention is disclosed in the accompanying drawing, in which Fig. 1 is a transverse section through a radiator cap looking from the rear showing the application of my invention;

Fig. 2 is a view similar to Fig. 1 but oi: a modified form, this form having a glass shaped section projecting without the radiaz torcap; and p N Fig. 3 is a similar View of a further medi ficatlon in which one end of the heat cator tube leads into the overflow pipe.

Referring to Fig. 1, 1 indicates the shell of the radiator and 2 the upper. tank thereof. This tank or container has anupwardly projecting annular flange 3 to which is rigidly attached an externally threaded collar 41 projecting through theshell 1. Over the collar 4 there is applied the supporting part or cap 5 having openingst} and 7 at its upper portion and these openings are provided with bushings 8 and 9 made of heat resisting materiah f The tube of my indicator is shown 'at10, the end 11 of which is funnel shaped and projects below the surface 0-: thewater 12 in the radiator. The tube is offset at 32 and at its upper'end is U-shapedand has a leg 12 passing through the bushing 8 and forming a continuation of the offset 32 while the leg 13 forms a return bent portion passing through the bushing 9 and terminating at 14 within the air space over the water 127. The legs 12 and 13 are connected by the horizontal portion lo to which is applied a heat sensitive paint 16 which has the property of changing its color when heat above a certain degree is applied thereto. I

The ends 11 and 1 1 of the tube 10 are open and as the water approaches the boilin point the funnel 11 causes the water an 1 consist of a bent tube of glass having its ends disposed Within the ,metallic tube sections 10 and 14C. Numerals 17 18 and 19 indicate thgee drops of water passing through the tu e. Referring to the species of Fig. 3, it will be noted that the collar 4 is internally threaded for the reception of a threaded member 5 of my heat indicator device indicated as a whole at 20. The collar 4: has e an annular shoulder 21 upon which rests the disc 22 having tongues 23 fitting into recess 24 of the collar 4. The disc 22 is loosely held "place in Fig. 3.

' top is concave and serves as'a reflector for the heat sensitive paint surface 16. As

shown in. Fig. 3, the paint is applied over a smallscreen attached to the curved part 30, although we may apply the paint directly .to the tube at the part 31. Obviously the reflector may be applied to the devices shown in Figs. land 2.

The tube 10of the species or Fig.3 has its end 11 disposed within the overflow pipe 29 and its. upper endlaf returnbent and openinginto the airspace at the top ofthe radiator orit may extenddown into the water in the same manner as the part 1011 of Fig. 1, in which case the circulation would be in the reverse direction from what takes The return bent portion of the tube 10 is circular as indicated at 30 and has a section 31- which passes tothe rear of the painted surface 16 and extends into a recess 33 "in the lower portion of the reflector 25. V

The passage of the vapor through the open end 14 of the tube 10", through the loop 'portion 30 and into the overflow pipe 29 leading to the atmosphere will cause the heated vapor to pass the paintedsurface 16.

and when a sufliciently high degree of temperature is reachedthe color of the painted surface will change.

The operation ofthe device shown in Figs.

1 and dis as follows: Assuming that the color of the heat sensitivejpaint is normally yellow, when the: heated vapor passes throughthetubes 10.'or 10 and is sufiiciently hot, it will act upon the painted surface and causethe color to change, for instance to a brlght red. As the vapor cools down the color change, will reverse.

We claim:

1. A heat indicating device comprising a container having an opening,a closure therefor,'a hollow member extending through said closure and having its end return bent and also passing through said closure, one end of said member bein exposed to fluid within the container, and means for indicating temperature difl'erences in saidfluid as the lat ter flows throughsaid member upon change of temperature thereof.

' 2. The combination of'claim'l, the opposite end of said member extending into the medium, the temperature of Which is to be indicated. i

3. The combination of claim l,the opposite end'of said member being of tunnel shapeand extendingbelow the surface of a liquid the temperature of which is to be indicated.- 7 I 4. The combination of claim 1, said means comprising a heat sensitive paint applied to that portion of the member extending through said closure.

5. The combination of claim 1, said return bent portion being of inverted U-shape, and a coating of heat sensitive paintapplied to the base of the U. I

6. Means for indicating the condition of liquid in a container comprising a tube extending down into said liquid from above the funnel shaped opening, means associated with said tube for giving a visible indication when fluid passes through said tube, and means for returning said fluid to said container.

7. A heatindicating devicecomprising supporting part, a heat transmitting member extending through said part and having its level thereof'and adapted to allow the fluid to pass therethrough, said tube having a end return'bent and passingthrough said a part, one end ofsaid member being exposed to the temperature differences of the body whose thermal condition'is'to be indicated,

' and means at the return bent portion for indicating said diflerences.

8. In a heat'indicating device, a container having a closure, a hollow tube extending through said closure at a plurality of openings'therein, bushings in said openings surrounding said tube, and means on said tube for indicating temperature differences.

9. Ina heat indicator, a container havin aclosure, a .U-shaped tube passing througfl said closure the legs of said U being of unequal len'gth, and means on said tube for indicating temperature differences of the body to'which the indicator is applied.

In testimony whereof we afHx our signatures. V

' JESSEE. ESHBAUGH.

HERMANC. GANTZ. 

